A series of marine natural products isolated from the sponge of Verongida have been intensively studied due to the presence of alkaloids with one, or more bromotyrosine residues. Many of these alkaloid metabolites show interesting bioactivity and cytotoxic properties in tumor cell lines. The natural product, 11-Deoxyfistularin-3 is cytotoxi against the estrogen dependant human breast carcinoma cell line MCF-7 (LD50 = 17 mg/L). The World Health Organization (WHO) recently predicted that death caused by cancer is expected to increase to 13.1 million by 2030. Among all other deadly cancers, invasive breast cancer is the most recurrently diagnosed malignant tumor among women (31% in the US and 27% in Europe) and the second leading cause of cancer related death subsequent to lung cancer. Women have a 32% lifetime risk of developing breast cancer and 15% risk of breast cancer causing death in the US. We plan to address the challenge of improving the aforementioned statistics through developing derivatives of the natural product, 11-deoxyfustularin-3, that will have sub-micromolar activity against MCF-7 breast cancer. This research project has three main objectives. The first objective is to develop a synthetic methodology that can be applied toward the asymmetric total synthesis of the biologically active natural product, 11-deoxyfistularin-3. Secondly, we plan to construct synthetic analogues of the natural product to determine if a segment of the natural product can also display biological activity against MCF-7 cells. Our final objective is to determine if any of the MCF-7 active synthetic analogues and the natural product can effectively bind to estrogen receptors. The data generated from these binding assays will lead to theoretical docking studies of the ligand-receptor interactions of the biologically active compound and the estrogen receptor, and the generation of a structure-activity relationship profile of these compounds could potentially lead to the construction of synthetic analogues that possess sub-micromolar activity against breast cancer cells.